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Articles 61 - 90 of 1200
Full-Text Articles in Mechanical Engineering
Autonomous Control Of A Hybrid Unmanned Aerial Towed System On A Moving Platform, Zachary M. Miller
Autonomous Control Of A Hybrid Unmanned Aerial Towed System On A Moving Platform, Zachary M. Miller
Graduate Theses and Dissertations (2019 - present)
With tethered rotor drones being more popular for aerial surveillance, moving platforms for tethered drones are being researched. However, these systems require constant power to the rotor drones for stabilization. With this difficulty in power consumption, a hybrid drone solution is presented. The hybrid drone is similar to an airplane, with quadcopter motors attached for stabilization and thrust when not moving.
The controller for the hybrid drone was tested and verified in simulation. The simulation of the system was built in Fortran and consists of a driver, a tether, and a hybrid drone. The driver was modeled after a generic …
Cruising On The Beach (Cob), Juan Diego Molina Ii, Ashley Kianna Burga
Cruising On The Beach (Cob), Juan Diego Molina Ii, Ashley Kianna Burga
Biomedical Engineering
This report details the design and development process of Cruising on the Beach (COB), a modular motorized wheelchair intended to improve beach accessibility for high school students with mobility impairments. The project aimed to create an affordable, portable, and sand-capable device using balloon wheels, an adjustable control panel, and a customizable base. Extensive background research, market analysis, design modeling, and test plans were completed. However, final fabrication was not achieved due to financial constraints and limited access to industrial machining tools needed for custom metal components. Despite these setbacks, the project delivered a robust conceptual design and a fully …
Cellulose Recovery From Waste Denim Fabrics Through Indigo Vat Dye Reduction And Spandex Dissolution, Tito N. Venance
Cellulose Recovery From Waste Denim Fabrics Through Indigo Vat Dye Reduction And Spandex Dissolution, Tito N. Venance
Tanzania Journal of Engineering and Technology (TJET)
This study addresses environmental conservation by tackling end-of-life management for post-consumer denim garments through the recycling of cotton fibres from waste denim. The purification process involved dithionite reduction of vat dyes in the presence of an alkali followed by selective dissolution of spandex using N,N-dimethylformamide (DMF). Optimal conditions for dye removal were determined at 90°C for 120 minutes with sodium hydroxide at 25 g/L, sodium dithionite at 6 g/L and PVP at 4.5 g/L, while spandex extraction was achieved using a 5% DMF solution at 70°C for 4 hours. Ultraviolet (UV)-vis spectrophotometric analysis indicated a significant increase in whiteness (DL*). …
Semi-Autonomous Trash Bot, Ben Leon, Ethan Mashburn, Connor Olivera, Dillon Michael Wood
Semi-Autonomous Trash Bot, Ben Leon, Ethan Mashburn, Connor Olivera, Dillon Michael Wood
ATU Scholars Symposium
Title: Semi-Autonomous Trash Robot
Authors: Benjamin Leon, Ethan Mashburn, Connor Olivera, Dillon Wood
Abstract: Environmental pollution is becoming more worrying every day as megatons of human waste persist in vast amounts in our ecosystems. The existing waste collection methodologies, with the labor, time, and cost components combined, make the process cumbersome. A potential solution could be an automated waste collection robot that incorporates AI into a cheap system that autonomously detects trash. This report proposes a machine that may be manufactured to adequate standards in terms of size and cost and deployed in various environments, with the ultimate goal of …
Wind-Resilient Solar: Harnessing Cfd For Enhanced Load Estimation, Aly Mousaad Aly
Wind-Resilient Solar: Harnessing Cfd For Enhanced Load Estimation, Aly Mousaad Aly
Faculty Publications
Solar panels are a cornerstone of renewable energy infrastructure, playing a pivotal role in global sustainability efforts. To ensure their resilience and long-term viability, accurate wind load estimations are essential for designing supporting structures, which account for nearly 50% of their total cost. However, traditional building codes lack comprehensive guidance for solar panels, resulting in inconsistent estimations due to discrepancies in scaled wall-bounded wind tunnel testing methodologies. These inaccuracies pose safety risks, increase costs, and hinder adoption. Emerging technologies like computational fluid dynamics (CFD) simulations offer a promising alternative by enabling full-scale analysis under realistic conditions of complete turbulence. This …
Advancing Solar Farm Resilience: Cfd-Driven Wind Load Optimization, Aly Mousaad Aly
Advancing Solar Farm Resilience: Cfd-Driven Wind Load Optimization, Aly Mousaad Aly
Faculty Publications
This study investigates wind load design methods for ground-mounted solar panels and arrays by comparing Computational Fluid Dynamics (CFD) simulations with design standards. A case study of a solar farm impacted by Hurricane Maria examines the effects of elevation height, tilt angle, and variations in the American Society of Civil Engineers (ASCE) standards on wind loads and structural failure. Turbulence models, including Reynolds Stress Model, k–ε Model, and Large Eddy Simulation (LES), are used to analyze wind pressures, lift, drag, and peak pressures. Results show Phase 1 experienced higher wind loads than Phase 2 due to design differences. A cost-benefit …
Helical Products Parts Display Stand, Binh Nguyen, Emily Yuan Mendyke, Zoe Porter
Helical Products Parts Display Stand, Binh Nguyen, Emily Yuan Mendyke, Zoe Porter
Mechanical Engineering
Helical Products needs a new product display stand that will demonstrate their custom springs, couplings, and u-joints. Their current display stand, a marble run contraption, is large, loud, and difficult to transport, so they would like the new stand to remedy these issues. The goal of this senior project is to create a display stand that captures the attention of their customers with dynamic product demonstrations while addressing the issues outlined above.
The new display stand is also a marble run contraption, but instead of being almost 4 feet tall and 3 feet long, it is 23” tall, 26.25” long, …
The Effect Of Hot Machining Of Difficult-To-Machine Materials On The Form Accuracy In The Turning Process, Ahmed Yehia Kamal, Samy F. M. Assal, Ahmed M. El-Kassas, Ahmed A. Hawam
The Effect Of Hot Machining Of Difficult-To-Machine Materials On The Form Accuracy In The Turning Process, Ahmed Yehia Kamal, Samy F. M. Assal, Ahmed M. El-Kassas, Ahmed A. Hawam
Journal of Engineering Research
Form accuracy of machined parts is crucial to the interchangeability in production as well as the function of the part and its expected useful life. Numerous studies investigated the form accuracy in traditional machining operations but none of them considered this issue in hot machining. In this technique, a difficult-to-machine workpiece is preheated to soften its material and reduce the cutting force. In this paper, the form accuracy represented in roundness, tape, and straightness of hot turned AISI 304L parts are investigated. The results showed that the hot condition has a minimal effect on the form accuracy which confirms the …
Intelligent Turning Cyber-Physical Systems Modeling Using Sysml, Prithbey Raj Dey, David Lee Enke, Mario F. Buchely
Intelligent Turning Cyber-Physical Systems Modeling Using Sysml, Prithbey Raj Dey, David Lee Enke, Mario F. Buchely
Engineering Management and Systems Engineering Faculty Research & Creative Works
Cyber-Physical Systems (CPS) support industrial automation that incorporates people, hardware, signal, computation, and control using networking to achieve desired results. The complex automated CPS design demands a standard and comprehensive approach to appropriately identify the system requirements, define the architecture, and model the relationships among the software and hardware components. Systems Modeling Language (SysML) provides the capability for a comprehensive modeling to capture the desired design requirements in the systems architecture. SysML enables performance estimation of the model by analyzing constraints while identifying interactions among the components through various behavioral diagrams. In this paper, SysML is applied to the design …
Collaborative Ai: Oer Materials For Exploring Ai As A Partner Rather Than A Tool, David Smith
Collaborative Ai: Oer Materials For Exploring Ai As A Partner Rather Than A Tool, David Smith
Open Educational Resources
The Collaborative AI Open Educational Resource (OER) explores how artificial intelligence can act as a creative and analytical collaborator rather than a tool. Centered on the Balanced Blended Space (BBS) framework and the philosophy of the Center for Holistic Integration (CHI), the OER includes curriculum materials, theoretical models, and live research environments. It offers an interesting approach to blending physical, virtual, and conceptual spaces through shared human–AI agency and invites ongoing participation in interdisciplinary meta-projects.
Development Of Planetary Drive System For Formula Sae Electric Race Car, Brian Wong, Bradley Maruoka, Joshua Charles Fine, Madison Kai
Development Of Planetary Drive System For Formula Sae Electric Race Car, Brian Wong, Bradley Maruoka, Joshua Charles Fine, Madison Kai
Mechanical Engineering
Hub motors are compact electric motors mounted directly on each outboard wheel hub. Utilized in Formula SAE and Formula Student vehicles, this configuration offers several advantages over traditional drivetrains, including packaging optimization within the chassis, vehicle traction, and improved efficiency. Although hub motors are not yet common in 4WD vehicles, they are being explored for use in EVs and may become more common in the future. Every year, Cal Poly Racing FSAE designs and builds a formula-style race car. To improve drivetrain performance, the team is investigating the achievability of a hub motor 4WD drivetrain, requiring extensive research, development, and …
Improving The Viability Of Continuous Fiber Reinforced Composite Materials In Extreme Temperature Applications And Additive Manufacturing, Ryan A. Warren
Improving The Viability Of Continuous Fiber Reinforced Composite Materials In Extreme Temperature Applications And Additive Manufacturing, Ryan A. Warren
Shelby Hall Graduate Research Forum Presentations
Presentation slides for a presentation given at the 1st annual Shelby Hall Graduate Research Forum at the University of South Alabama.
Numerical Simulation Of Airflow Properties Of The Naca 6420 Airfoil Using The Transition Rans K-Ε Model, Oluwaseyi O. Alabi, Saidat A. Salisu, Oyeyemi T. Aforolagba -Balogun, Temitope A. Ladigbolu, Ayotunde O. Fasina, Anas Bala
Numerical Simulation Of Airflow Properties Of The Naca 6420 Airfoil Using The Transition Rans K-Ε Model, Oluwaseyi O. Alabi, Saidat A. Salisu, Oyeyemi T. Aforolagba -Balogun, Temitope A. Ladigbolu, Ayotunde O. Fasina, Anas Bala
Al-Bahir
This study investigates the airflow properties around the airfoil using numerical simulation, addressing the longstanding challenge of accurately predicting transition phenomena in turbulent flows. The importance of this research lies in its potential to improve the design and performance of airfoils in various engineering applications, such as wind turbines, and aircraft. A custom 2-dimensional airfoil model was created using Airfoil instruments, featuring a 6% maximum curvature, 40% curvature position, and 20% thickness. COMSOL Multiphysics software performed computations at a velocity of over 19 hours, with data analyzed at 60-minute intervals. The Transition turbulent model was employed to simulate the airflow …
Effects Of Thermal Shock Protection Methods On Pressure Measurements In A Rapid Compression Machine, Myeji Materego
Effects Of Thermal Shock Protection Methods On Pressure Measurements In A Rapid Compression Machine, Myeji Materego
Tanzania Journal of Engineering and Technology (TJET)
The study investigates the impact of thermal shock protection methods on pressure measurements in Rapid Compression Machines (RCMs). It focuses on the performance of various pressure transducers, specifically 601A, 701A, 6061B, and 7005, under atmospheric initial conditions. The research emphasizes the importance of mounting techniques and coatings, revealing their significant effects on pressure trace accuracy. Special mounting adaptors for the pressure transducers were designed and manufactured, this enabled simultaneous measurements for all transducers to be made in a single compression stroke. Instantaneous pressure within combustion chamber was measured when air was compressed in RCM from initial pressure and temperatures of …
Development Of A Drive-Rod Unified Variable Pitch Control Mechanism For Small-Scale Horizontal Wind Turbines, Ayman I. Bakry, Mohamed Elfouly, Omar Mehrez
Development Of A Drive-Rod Unified Variable Pitch Control Mechanism For Small-Scale Horizontal Wind Turbines, Ayman I. Bakry, Mohamed Elfouly, Omar Mehrez
Journal of Engineering Research
Typically, small-scale wind turbines use either a breaking equipment or stall control methods once the wind speed exceeds its rated value. This is to limit the power extracted from the wind turbines which largely depends on the blades' shape and pitch angle. Most of small-scale wind turbines are of fixed pitch angle to avoid complexity and cost. In this work, a novel drive-rod unified variable pitch drive mechanism is proposed for blades pitch control for small-scale horizontal wind turbines. The mechanism is powered by a DC motor coupled with a lead screw which in turn is connected to the pitch …
Pd Controller Design For Automotive Magnetorheological Semi-Active Suspension System, Ayman I. Bakry, Emad M. S. El-Said, Ahmed Shehata Gad, Ahmed Abd Almoez, Omar Mehrez
Pd Controller Design For Automotive Magnetorheological Semi-Active Suspension System, Ayman I. Bakry, Emad M. S. El-Said, Ahmed Shehata Gad, Ahmed Abd Almoez, Omar Mehrez
Journal of Engineering Research
Recently, there is a tendency towards the utilization of magnetorheological (MR) dampers in electrical vehicles (EV) due to its adaptability of active control devices with lower requirement of large power sources compared to the active damping systems. This paper investigates the performance of the most used control technique for MR dampers used in EV, the PID controller, under different road conditions. In this investigation, the Dynamic-Damper-Motor System (ADM-EV) is used as the EV suspension system model. Meanwhile, modified Bouc-Wen model is used as the MR damper model. The design procedure for the optimum design of the system controller parameters is …
A Structural Evaluation And Design Optimization Of A Tow Bar For Disabled Snowmobiles, David M. Pevic
A Structural Evaluation And Design Optimization Of A Tow Bar For Disabled Snowmobiles, David M. Pevic
Masters Theses
Snowmobile tow bars are devices used to rigidly connect two snowmobiles, such that a disabled snowmobile can be recovered from a remote location with a working snowmobile. These devices, however, are not widely used or readily available. An existing tow bar design was evaluated and redesigned to improve its structural capacity and performance. This evaluation provided a baseline to quantify improvement and included Finite Element Analysis (FEA), Design Failure Mode and Effect Analysis (DFMEA), and Design for Assembly analysis (DFA). A review of existing snowmobile tow bar patents was also performed. An updated design was then fabricated and similarly evaluated. …
Feasibility Study Of A Smart Insole With Triboelectric Energy Harvesters For Early Flatfoot Detection, Mohammad Alghamaz
Feasibility Study Of A Smart Insole With Triboelectric Energy Harvesters For Early Flatfoot Detection, Mohammad Alghamaz
Mechanical Engineering Theses
This study introduces a self-powered smart insole system designed for real-time monitoring of foot health, with a specific focus on detecting flatfoot conditions. The insole integrates multiple triboelectric energy harvesters strategically positioned to capture electrical signals generated from ground reaction forces during daily activities such as walking, jogging, and running. Proof-of-concept testing was conducted on a single participant under two conditions: a healthy foot and a simulated flatfoot created by reducing the medial arch height by approximately 70\. In the healthy foot trials, the system demonstrated consistent and reliable performance, with negligible electrical output from the medial arch sensor, as …
Stress Analysis Of Anisotropic Inclusion Problems Using Complex Variables, Liming Chen
Stress Analysis Of Anisotropic Inclusion Problems Using Complex Variables, Liming Chen
Mechanical and Aerospace Engineering Dissertations - Archive
This research presents an analytical framework for determining stress fields in an elastic medium containing a circular anisotropic inclusion embedded in an infinitely extended isotropic matrix subjected to far-field uniform stresses. Stress distributions within both the inclusion and the matrix are described using classical stress functions, widely employed in two-dimensional elasticity theory.
To manage the complexity of the mathematical derivations, symbolic computation software (Mathematica) is used to streamline the analysis and obtain closed-form solutions. This approach overcomes traditional computational barriers that have limited the practical application of complex variable methods (CVM) in elasticity.
The methodology builds upon the foundational work …
Nonlinear Bump Stiffness Model And Its Effect On Structural Stiffness And Nonlinear Rotordynamic Characteristic Of Foil Bearing, Woongeon Lee
Mechanical and Aerospace Engineering Dissertations - Archive
Bump foils are the most widely used in foil bearings, but the behaviors of bump foils are complicated, and their characteristics have been a focus of research for decades. Bump foils are usually modeled as stiffness and damping are accounted for through interactions with shaft eccentricity, loading, shaft speed and excitation frequency. These nonlinear characteristics of the bump foil of radial foil bearings can be observed during both manufacturing and operational processes because of their inherent structural properties such as bump geometry, forming process, age-hardening process and complicated contact behavior with bearing housing. These nonlinear characteristics are one of the …
Multi-Objective Design Optimization Of Hypoid Geared Rotor Systems, Xinqi Wei
Multi-Objective Design Optimization Of Hypoid Geared Rotor Systems, Xinqi Wei
Mechanical and Aerospace Engineering Dissertations - Archive
Hypoid gears represent one of the most generalized and complex forms of gearing, widely used for power transmission of skew shafts in vehicles, aviation, and marine transmission applications. Optimizing their performance remains challenging due to the complex tooth surface and contact behavior. Specifically, the design parameters of the tooth surface are multi-scale, interdependent, and subject to strong constraints, leading to strong nonlinearity and an ill-conditioned Jacobian matrix in the parameter identification model. Moreover, feasible and insensitive contact conditions are difficult to constrain due to the inherent complexity of local conjugate contact between the meshing surfaces. These challenges significantly increase optimization …
Viscoelastic Property Analysis Of A Magnetorheological Elastomer Micropump For Insulin Delivery In Type 1 Diabetes, Victor Buitimea
Viscoelastic Property Analysis Of A Magnetorheological Elastomer Micropump For Insulin Delivery In Type 1 Diabetes, Victor Buitimea
College of Graduate Studies: Theses & Dissertations
Over two decades, there has been a significant rise in awareness regarding Type 1 Diabetes (T1D), leading to a deeper comprehension of numerous variables, including hereditary factors, patterns of occurrence, and health challenges. According to the Type 1 Diabetic Index, around 8.7 million people worldwide are affected by this chronic autoimmune illness marked by a lack of insulin and hyperglycemia. The introduction of artificial pancreas systems could save more than half a million patients by 2040. Despite the availability of various insulin delivery technologies that are offered to diabetic patients, many still are skeptical of this modern system. The issues …
Controlling Nitrogen Pickup During Induction Melting Of Ultrahigh-Strength Cr-Ni-Mo-V Steels, Kingsley T. Amatanweze, Viraj A. Athavale, Mario F. Buchely, Laura N. Bartlett, Ronald J. O'Malley, Daniel M. Field
Controlling Nitrogen Pickup During Induction Melting Of Ultrahigh-Strength Cr-Ni-Mo-V Steels, Kingsley T. Amatanweze, Viraj A. Athavale, Mario F. Buchely, Laura N. Bartlett, Ronald J. O'Malley, Daniel M. Field
Materials Science and Engineering Faculty Research & Creative Works
Nitrogen pickup during air induction melting can result in porosity and a loss of fracture toughness in ultrahigh-strength quenched and tempered steel castings. Nitrogen atoms are easily adsorbed into liquid steel upon exposure to the air, and argon shrouding alone has limited effectiveness. Previous studies have shown that proper charge sequencing and maintaining a high amount of dissolved oxygen in the melt prior to tapping and deoxidation can limit nitrogen pickup in the melt. In the current study, the effect of melt practice and charging procedure on nitrogen pickup was studied as a function of hold time in a series …
Effect Of Gating Design On Filling And Inclusion Control In An Al-Killed Cr-Mo-Ni Steel, Kingsley T. Amatanweze, Koushik Balasubramanian, Soumava Chakraborty, Viraj A. Athavale, Mario F. Buchely, Laura N. Bartlett, Ronald J. O'Malley, Daniel M. Field, Krista R. Limmer, Katherine M. Sebeck
Effect Of Gating Design On Filling And Inclusion Control In An Al-Killed Cr-Mo-Ni Steel, Kingsley T. Amatanweze, Koushik Balasubramanian, Soumava Chakraborty, Viraj A. Athavale, Mario F. Buchely, Laura N. Bartlett, Ronald J. O'Malley, Daniel M. Field, Krista R. Limmer, Katherine M. Sebeck
Materials Science and Engineering Faculty Research & Creative Works
The effect of gating system design on the inclusion population and size distribution in an aluminum-killed low-alloy advanced high strength steel casting was studied. A mold with four different gating systems: pressurized and non-pressurized with side risers, naturally pressurized with a side riser, and naturally pressurized with a top riser, was designed using computational fluid dynamics and solidification software. The design allowed inclusion populations in castings produced with each gating system to be compared during the same pouring event. Samples taken from different positions just below the top surface of each casting were analyzed using an SEM/EDS system with automated …
Parametric Analysis Of Water Jet Descaling Efficiency Of Reheated Continuously Cast Thin Slab, Tochukwu P. Ojiako, Mario F. Buchely, Simon Lekakh, Ronald J. O'Malley, Richard Osei, Taha Tayebali
Parametric Analysis Of Water Jet Descaling Efficiency Of Reheated Continuously Cast Thin Slab, Tochukwu P. Ojiako, Mario F. Buchely, Simon Lekakh, Ronald J. O'Malley, Richard Osei, Taha Tayebali
Materials Science and Engineering Faculty Research & Creative Works
Efficient oxide scale removal is critical for maintaining surface quality and process efficiency in steel manufacturing. This study optimizes water jet descaling by evaluating the performance of flat and rotary jet nozzles under varying process parameters. Using a combined approach of experimental analysis and computational fluid dynamics, it investigates the influence of pressure (138–275 bar), lead angle (0°, 15°, 25°), working distance (50–100 mm), and spray angle (15°–25°) on descaling efficiency. Findings indicate that flat jet nozzles achieve superior performance at short working distances due to concentrated impact forces, while rotary jet nozzles sustain efficiency over extended distances through dynamic …
Ioto: Never Open A Stiff Lid Again, Gabriel Portugal
Ioto: Never Open A Stiff Lid Again, Gabriel Portugal
Libraries Award for Undergraduate Scholarship
Background: From baby food to pickles, food jars are a common find in American homes. Unfortunately, the task of opening a stiff jar lid can be very difficult for consumers with lower grip strength, parkinsons, or arthritis. While there are a variety of products on the market to help make this easier, there exist few jar openers that can be used by these consumers. Objective: This project aimed to research and develop (R&D) an improved hands-free jar opener that is accessible for consumers with the most advanced cases of limited arm strength. Methods: R&D followed a Design Thinking approach with …
Development Of Microfluidic Device To Monitor The Contamination In Drinking Water Using Impedance Spectroscopy, Pornpipat Oupchan
Development Of Microfluidic Device To Monitor The Contamination In Drinking Water Using Impedance Spectroscopy, Pornpipat Oupchan
Chulalongkorn University Theses and Dissertations (Chula ETD)
Microplastic contamination is a growing concern, as microplastics have been found in brain tissue and can enter the body through consumption. The objective of this research is to develop a microfluidic device to monitor microplastic particles by using electrical impedance spectroscopy principles. The device operates based on a flow-through principle. The configuration of electrode consists of copper-based cylindrical electrode with diameter of 300 micrometer and a center-to-center spacing of 2000 micrometer. The electrodes are designed to be replaceable. The microchannel has a rectangular cross-section with a width of 2000 micrometer and a height of 1000 micrometer. The microfluidic device was …
การทำความเย็นส่วนบุคคลโดยใช้วัสดุเปลี่ยนสถานะสำหรับบุคลากรที่สวมใส่ชุดป้องกันการติดเชื้อส่วนบุคคล, พรพุทธ วิสุทธิวัชรกุล
การทำความเย็นส่วนบุคคลโดยใช้วัสดุเปลี่ยนสถานะสำหรับบุคลากรที่สวมใส่ชุดป้องกันการติดเชื้อส่วนบุคคล, พรพุทธ วิสุทธิวัชรกุล
Chulalongkorn University Theses and Dissertations (Chula ETD)
ชุดป้องกันส่วนบุคคล (PPE) เป็นอุปกรณ์สำคัญที่ช่วยลดความเสี่ยงในการติดเชื้อของบุคลากรทางการแพทย์ อย่างไรก็ตาม การสวม PPE เป็นเวลานาน โดยเฉพาะในสภาพอากาศร้อนและชื้นอย่างประเทศไทย มักนำไปสู่การกักเก็บความร้อนในร่างกาย การระบายความร้อนลดลง และเกิดความไม่สบาย ความเหนื่อยล้า รวมถึงภาวะเครียดจากความร้อน งานวิจัยนี้จึงได้พัฒนาแบบจำลองชีวความร้อนอย่างง่าย (simplified bioheat model) โดยอ้างอิงโครงสร้างแบบจำลองแบบ passive ของ Fiala และเสริมด้วยการตอบสนองทางสรีรวิทยาแบบ active ที่จำเป็น เพื่อใช้ทำนายอุณหภูมิของร่างกายและประเมินความสบายทางความร้อนเมื่อสวม PPE ร่วมกับการระบายความร้อนด้วยวัสดุเปลี่ยนสถานะ (Phase Change Material: PCM) ผลการตรวจสอบความถูกต้องเทียบกับแบบจำลองอ้างอิงของ Fiala แสดงให้เห็นว่าแบบจำลองที่พัฒนาขึ้นมีความแม่นยำดี โดยมีความคลาดเคลื่อนของอุณหภูมิอยู่ภายใน ±0.2°C นอกจากนี้ผลการจำลองยังพบว่า PCM สามารถลดความเครียดจากความร้อนและเพิ่มความสบายทางความร้อนอย่างมีนัยสำคัญในช่วง 60 นาทีแรกของการทำงาน แม้ว่าประสิทธิภาพจะลดลงเมื่อ PCM หลอมละลายเต็มที่ก็ตาม ข้อจำกัดของงานวิจัยนี้ คือ แบบจำลองตั้งอยู่บนสมมติฐานของสภาวะอากาศร้อน (เริ่มต้นที่ 30°C) ทำให้ยังไม่สามารถแทนสภาวะอากาศเย็นได้อย่างสมบูรณ์ อีกทั้งไม่ได้พิจารณาการตอบสนองทางสรีรวิทยาระยะยาว เช่น ภาวะขาดน้ำ ความเหนื่อยล้า หรือความเครียดเชิงกลจากน้ำหนัก PCM ที่เพิ่มขึ้น ถึงแม้จะมีข้อจำกัดดังกล่าว แบบจำลองนี้ยังคงสามารถทำนายอุณหภูมิร่างกายและค่าความรู้สึกทางความร้อนแบบพลวัต (DTS) ได้อย่างมีประสิทธิภาพก่อนการใช้งานจริง จึงสามารถนำไปใช้เป็นเครื่องมือช่วยวางแผนระยะเวลาการทำงานที่ปลอดภัย และช่วยกำหนดปริมาณ รวมถึงตำแหน่งการติดตั้ง PCM ที่เหมาะสม ผลลัพธ์จากงานวิจัยนี้สามารถเป็นฐานข้อมูลสำคัญสำหรับการออกแบบชุด PPE ที่ปลอดภัย และช่วยลดภาระความร้อนสำหรับบุคลากรทางการแพทย์ในสภาพแวดล้อมร้อนชื้นได้ดียิ่งขึ้น
Analysis Of Ptfe Radial Lip Seals For Wheel Bearing Applications, Madison Vogt
Analysis Of Ptfe Radial Lip Seals For Wheel Bearing Applications, Madison Vogt
Theses and Dissertations--Mechanical and Aerospace Engineering
A numerical analysis was conducted to investigate the viscoelastic effects of nonlinear materials on the sealing zone and contact pressure distribution of radial lip seals in a conventional geometric topology. The use of nonlinear materials in radial lip seal applications is desirable to improve operation and reliability of rotating machinery due to their high operating temperatures, chemical compatibility, and low friction coefficients. Examples include, but are not limited to, seals within industrial air compressors, turbine engines, aircraft landing systems, chemical processing equipment, and Freon pumps. This work focuses on analyzing the nonlinear viscoelastic response of pure Polytetrafluoroethylene (PTFE) and PTFE …
Growth Kinetics And Stability Of Metal Halide Perovskite Nanocrystals: Influence Of Stirring Speed And Water Exposure, You-Lin Huang
Growth Kinetics And Stability Of Metal Halide Perovskite Nanocrystals: Influence Of Stirring Speed And Water Exposure, You-Lin Huang
Theses and Dissertations--Mechanical and Aerospace Engineering
Cesium lead bromide (CsPbBr3) perovskite nanocrystals (NCs) have garnered significant interest due to their exceptional optoelectronic properties, including high photoluminescence quantum yield, tunable bandgap, and excellent carrier dynamics. These attributes make them promising candidates for applications in light-emitting diodes, photovoltaics, and sensing technologies. However, optimizing their synthesis and improving their environmental stability remain critical challenges. This dissertation explores the growth kinetics of CsPbBr3 NCs, focusing on the effects of stirring speed and water exposure on their structural and optical properties.
The synthesis of CsPbBr3 NCs was performed using both mechanochemical (MC) and antisolvent methods, enabling an …